Touch pads, touch screens and other input-sensing devices have a broad range of applications including computer systems, mobile phones, media players, personal digital assistants, gaming platforms, and other electronic devices. Suitable technologies include a variety of resistive and capacitive-coupled sensor systems, as well as optical, electromagnetic, and surface acoustic wave devices.
In capacitive sensing systems, a conducting grid may be utilized, for example with sets of orthogonal traces separated by a dielectric insulator. The grid functions as a capacitive array, which is sensitive to contact (or proximity) based on changes in the corresponding voltage or charge capacity, for example as manifested in a current output. In resistive devices, contact with the input surface causes changes in resistance across the insulating layer, which is registered by an increase or decrease in corresponding sense currents.
Increasingly, capacitive, resistive and other touch-sensitive systems are incorporated into track pads and visual display devices, providing increased input sensitivity for more flexible device control. As device technologies advance, moreover, an increasing number of control functions can also be integrated into a single device or form factor, including, but not limited to, real-time operation and control of voice and data communications, messaging, media playback and development, gaming, internet access, navigational services, and personal digital assistant functions including alarms, reminders and calendar tasks.
As the range of electronics device functions increases, there is also a desire for more advanced touch screens, track pads, and other input devices. In particular, there is a desire for more advanced input systems that can be adapted to real-time control and display functions for an ever-wider range of different electronic device applications, including track pad and touch screen display devices with improved input sensitivity and tracking capabilities.